Electric heater



Oct. 25, 1927.

C. L. WRIGHT ELECTRIC HEATER Filed Dec. 12, 1925 IN V EN TOR.

WM ATTORNEYS.

Patented Oct. 25, 1927.

UNITED STATES.

PATENT OFFICE.

CHARLES L. WRIGHT, F CHICOIPEE FALLS, MASSACHUSETTS, ASSIGNOR T0 LAMB KNITTING MACHINE COMPANY, OF CHICOPEE FALLS, MASSACHUSETTS, A COR- PORATION OF MASSACHUSETTS.

ELECTRIC HEATER.

I Application filed December 12, 1925. Serial No. 75,038.

This invention relates to an improved electric heater for automobiles and is particular- .ly designed for use in an unheated garage. Heretofore, heating devices have been designed for connection to an electric light circuit and to be placed under the hood of an automobile to improve starting conditions during cold weather. My invention is of thls general character but embodies new and useful features designed to efficiently overcome many of the difficulties in maintaining an automobile ready for use during its idle period in cold weather.

These difficulties are to maintain a supply of preheated air at the carburetor, to keep the lubricating oil from getting too cold, and

to keep the cooling system from getting too cold. If such difliculties are to be overcome by electric heating means, and this means gives the most convenient source of heat, the

cost must be kept down or such means hecome impractical for reasons of economy alone. The principal objects of this invention are to economically and elliciently distribute the heat available from an electric heating unit to preheat the air for the carburetor, to heat the lubricating oil, and to heat the cooling system. These objects are attained by the specially designed means so shown in the accompanying drawings by way of illustration of one preferred form of the invention.

' In the drawings:

, Fig. 1 is a top plan view of my special 36 heat distributing means;

Fig. 2 is a transverse sectional view taken on the line 2-2 ofFig. 1; 7

Fig. 3 is a longitudinal sectional view taken on the line 33 of Fig. 1; and

Fig. 4 is a perspective view of a portion of the front end of an automobile with the be described. Anarrow rim portion 7 sur-.

rounds the portion 3 and is purposely spread out so as to enclose a substantial area with the portion 3. This area is subdivided by grid work made up of ribs 5 instove lifter or poker.

tegral with portion 3 and rim portion 7 and extending across portion 3 in the shape of radiating flanges 8. I prefer to have the ribs 5 of larger cross section adjacent the tubular portion 3 so that they taper out toward the rim 7 for a purpose to be described. It is clear by reference to Figs. 1 and 2 that casting 1 is provided with much more metal at and near tubular portion 3 thanyat rim 7 and that in my preferred form the quantity of metal is gradually less and less as ribs 5 approach rim 7. The latter is provided with an outwardly extending loop 19 at one end of portion 3 surrounding an opening 20 from which the casting can be hung when in not use.

Figs. 2 and 3 best illustrate one important feature of my structure. The casting 1 is so made that rim portion 7, ribs 5, tubular portion 3 and radiating flanges 8 are all arranged to extend from a single plane. This plane as seen in these figures is the bottom boundary or surface of all the parts except the tubular portion to which, as shown, such plane maybe tangent. By this arrangement, I provide a flat metal surface on my casting of substantial extent above which is a grid Work having a much larger metal surface in various and different planes all radiating outwardly from that portion of the casting designed to contain the heating unit through which the electric current passes.

The electric heating unit assembly will now be described in the form shown best 'in Fig. 3. A threaded tube 10 of insulating material like porcelain is screwed into the extension 12 of plug 13. The latter closes one end of the tubular portion 3 by threaded engagement as shown. A handle rod 14 extends from the plug and a heat insulating wire handle portion 15 is provided around 1 1 like the handle of an ordinary Ordinary conducting Wires 17 extend from a plug socket attachment 18 through handle 14 and plug 13 where they join a specially insulated heating Wire 20f nichrome metal, for example. This wire is carefully insulated with asbestos and is wound in the threads of the tube 10 and extends back through the center of the tube to join one of the wires 17. Suitable further secure the electric insulation, I may provide a wrapping of asbestos paper or other electric insulating material of heat resisting character around the wire and tube so as to fill the space between the wire and the tubular portion 3 of the casting. These precautions to insure the conditions of electrical insulation within the heater are important, particularly because of the fire risk involved in the use of the heater under the hood of an automobile. As seen in Fig. 3,

the plug 9' closes the tubular portion of casting 1 at the opposite end to the one where the wires are admitted to the heating unit. With the heating unit properly insulated and completely enclosed and sealed as shown, there can be no ingress or egress of gases or liquids, it being understood that the wires 17 with their insulation have a tight fit in the tubular handle portion 14. Thus the place where the heat is generated and where the highest temperature occurs, is sealed up securely against fire risk. In building up the apparatus, it is ordinarily advisable to pass the current through the nichrome wire with all the insulation covering it in place before assembly with the casting so as to completely oxidize or smoke out any material which may be found in the asbestos insulation, as cotton is frequently used as a carrier for the asbestos fiber in making electrical insulation. When this has" been done and the heating unit sealed in place, the electric heater as a whole is ready for use.

Fig. 4 illustrates adesirable position for the heater under the hood of an automobile and the particular advantages in the use due to the constructionfeatures will now be stated in connection with such a position. The flat side of the casting is laid against the flat side of the crank casing, as shown, so that there will be good contact between the two. If now the hood is closed and the current from an ordinary lamp socket turned on, the casting is evenly heated throughout its whole extent and this action is materially assisted by the distribution of the metal in the casting so as to distribute the heat uniformly over the large area of the casting before it has a chance to be taken away from the casting by conduction or radiation or create a fire risk at any portion of the casting. The flat surface of the casting is particularly designed to transfer the heat by conduction to the metal of the crank casing in this instance, or to the metal of the engine at any other suitable point where such metal will in turn conduct it to the lubricating oil. The surfaces of the casting above the fiat side are particularly designed to transfer the heat by radiation to the air under the hood in contact with the engine metal but particularly that in contact with the automobile radiator usually of honeycomb construction and thin walls. By placing the heating unit either near the radiator or near the carburetor, the heated air can be concentrated on one or the other. If a radiator cover is used to confine the heated air under the hood, the. heating of the cooling system will be greatly assisted.- In any event, the air under the hood is heated by the specially designed radiating surfaces of the heater casting and this air will be available for the carburetor use and to prevent the cooling system going to as low a temperature as it otherwise would in a cold garage. Thus the objects of my invention, namely to particularly direct heat to the oil, to the cooling system, and to the air for the carburetor, are accomplished by the structure described and in a particularly Well guarded manner regarding fire risk.

I desire to emphasize the advantage in one electrically operated heating device for distributing part of the heat from the heating unit by conduction and part by radiation and providing for a substantial distribution by each method. If all the heat were transferred by conduction or without special provision for radiation or with only an incidental transfer by radiation, such heat Would be absorbed by the engine metal to such an extent that the air under the hood would be heated very little. Since heat can be transferred easier by conduction through metal there would be a dissipation of heat throughout the mass of metal or the engine at such a rapid rate and such metal being of considerable mass would never give off much by way of radiation to the air under the hood. If, on the other hand, the transfer of heat were practically all by radiation and only incidentally by conduction, the an under the hood would be well heated but very little transferred to the mass of the engine metal or crank case for the lubricating oil. But by so constructing the heating casting so as to transfer a substantial part of its heat by conduction and a substantial part of its heat by radiation, a special heat transfer which will occur with the electric heating means I have shown and described, I provide a controlled division of the available heat for all the desired purposes. This arrangement gives me an added efiiciency obtainable from a given amount of heat units all directed to the desired end which is to maintain the starting conditions suitable during cold weather and at comparatively low cost both with regard to the initial installation for the purpose and to its operating cost. It is clear that my simple device can be produced at very low cost and is exceptionally convenient for the user.

What I claim is:

1. An electric heater for temporary use on an idle automobile comprising an electric heating unit, a single heat distributing casting with a recess for such unit, said casting forming a grating of comparatively light Weight in proportion to its area having a substantial area in one plane for transferring a substantial part of the heat from said unit by conduction and another area in various planes for transferring the remainder of such heat by radiation all for the purpose described. 7

2. An electric heater for temporary use on an idle automobile comprising, an insulated electric heating unit to generate heat, a heat distributing casting formed as a grating and provided with a chamber to receive said unit, means to close said chamber, said grating having a large flat area designed to transfer heat by conduction and a larger variously projected area designed to transfer heat by radiation all for the purpose described.

3. An electric heater for temporary use on an idle automobile comprising, an electric heating unit for generating heat in a concentrated space, a single casting surrounding such space and shaped in the form of a grating for distributing a substantial part of such heat by conduction and the remainder of such heat by radiation all for the purpose described.

4. An electric heater for temporary use on an idle automobile comprising, an electric heating unit for generating heat, a single casting formed as a grating for distributin such heat, said casting having a centr chamber occupied b the said heating unit, means to close sa-i chamber, said casting being provided with a substantial fiat surof said grating and a radiating surface on the opposite side of said casting, all for the purpose described.

6. An electric heater for temporary use on an idle automobile comprising, a tubular electric heating unit, a circular heat distributing casting having a tubular portion along one diameter and occupied by the unit, a narrow rim around its circumference and radiating cross members extending from the rim across said tubular portion and forming radiating ribs of substantial area with tapering sides from the tubular portion toward the rim, means to close said chamber and electric insulating means of heat resisting characteristics within the chamber between the heat generating wire of the unit and the metal of the casting, and a heat insulated handle for the heater through which the wires of the heating unit pass to the chamber all for the purpose described.

In testimony whereof I have affixed my signature.

CHARLES L. WRIGHT. 

